The conventional automotive airbag installation, whether for a driver's or passenger's side, customarily includes a reaction canister which encloses a folded airbag, a source of pressurizing gas which inflates the airbag upon occurrence of a crash of sufficient magnitude, and a rupturable cover which closes the mouth of the reaction canister. The cover is conventionally formed and configured as a part of the vehicle's interior aesthetics. A driver's side airbag module is normally installed within the confines of the steering wheel. The passenger side airbag is conventionally mounted within the dashboard facing the passenger. The covers are normally designed to split open under the influence of the expanding airbag. This is achieved by lines of weakness in the airbag cover, conventionally termed "tearseams". The tearseams are configured such that, when bursting, they form one or more hinged doors which release the airbag into the vehicle interior.
It is normally desirable to control the sequence of bursting of the tearseams to properly orchestrate the formation of the doors, while preventing the formation and discharge of cover particles into the passenger compartment. Accordingly, it is usually desirable to provide that one of the tearseams initiates the bursting action which thereupon flows into the remaining seams in sequential fashion. To this end the initial tearseam must be the most easily rupturable.
Several methods may be employed to form the rupturable tearseams. One of the simplest would be a series of perforations. However, this would probably not be aesthetically acceptable in a luxury or higher quality vehicle. A more common method is to form the tearseam as a groove along the hidden surface of the cover material, thereby thinning the cover material to an acceptable burst strength. However, one difficulty with this is that the initial tearseam may be visible from the front of the cover which is normally made of an injected molded material. This may be aesthetically undesirable.
Accordingly, it is a primary object of the present invention to provide an automotive airbag cover wherein the initial or primary tearseam lies in an extension of the cover which is normally hidden from sight. Another object is to provide such a cover having a novel transition permitting the rupture of the primary tearseam to proceed into tearseams in the main body of the cover to form the airbag release door. Other objects, features and advantages will become apparent from the following description and appended claims.